Outdoor readable liquid crystal display device

ABSTRACT

An outdoor readable liquid crystal display device ( 200 ) includes a liquid crystal panel ( 210 ), a backlight device ( 220 ) and a light source control device. The backlight device ( 220 ) includes a plurality of red light emitting diodes ( 220   r ), green light emitting diodes ( 220   g ) and blue light emitting diodes ( 220   b ). The light source control device is used to adjust the backlight device ( 220 ) based on the light intensity of ambient light. When the light intensity of ambient light is lower than a predetermined light intensity of the liquid crystal display device ( 200 ), the red light emitting diodes ( 220   r ), the green light emitting diodes ( 220   g ) and the blue light emitting diodes ( 220   b ) of the backlight device ( 220 ) are sequentially energized to emit lights at a predetermined time lag. When the light intensity of ambient light is higher than the predetermined light intensity, the red light emitting diodes ( 220   r ), the green light emitting diodes ( 220   g ) and the blue light emitting diodes ( 220   b ) of the backlight device ( 220 ) are energized to emit lights at the same time.

This application claims the benefit of Chinese patent application No.200810043215.6, titled “Outdoor-readable Liquid Crystal Display” andfiled with the State Intellectual Property Office on Apr. 3, 2008, whichis hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a liquid crystal display and inparticular to an outdoor-readable liquid crystal display.

BACKGROUND OF THE INVENTION

In recent years, Liquid Crystal Displays (LCDs) have been widely used inelectronics for representation of information due to their lightness,thinness, low power consumption, etc.

Conventional LCDs are broadly classified as either reflective ortransmissive. Unlike Cathode Ray Tube (CRT) displays andElectroluminescent (EL) displays, LCDs are not self-emissive. Atransmissive LCD is illuminated by a light source situated behind theLCD panel, and a reflective LCD is illuminated by ambient light. As aresult, transmissive LCDs are less subjected to the intensity of ambientlight and the contrast of the displayed image is higher, buttransmissive LCDs are less power efficient due to the presence of thelight source. Reflective LCDs are more power efficient because they donot need an additional light source, but the brightness and contrast ofthe displayed image in reflective LCDs are more subjected to theintensity of ambient light and the like. Particularly, their ability toresolve detail is notably limited in a dark environment.

A Field-Sequential Color Liquid Crystal Display (FSC-LCD) is a displaywith many advantageous features. The display switches on red, green andblue (R, G, B) backlights in sequence, which illuminate the displaypanel in sequence. That is, red, green and blue lights are applied ineach pixel in sequence. Due to image sticking, the red, green and blueimages are perceived by the observer as a continuous image.

Now refer to FIG. 1, a sectional view of the structure of a conventionalFSC-LCD 1. The FSC-LCD 1 includes a first upper substrate 10, a firstlower substrate 11, a first liquid crystal layer 12 provided between thefirst upper substrate 10 and the first lower substrate 11, and a firstbacklight device 13 for providing the light source of the FSC-LCD 1. Thefirst backlight device 13 including a plurality of red Light-EmittingDiodes (LEDs) 13 r, green LEDs 13 g and blue LEDs 13 b. First pixelelectrodes 111 and Thin-Film Transistors (TFTs) 112 used as switches areformed on the side of the first lower substrate 11 immediately adjacentto the first liquid crystal layer 12. The TFTs 112 are electricallyconnected to the first pixel electrodes 111. A first common electrode101 facing the first pixel electrodes 111 is formed on the side of thefirst upper substrate 10 immediately adjacent to the first liquidcrystal layer 12. A black base 102 is provided between the first commonelectrode 101 and the first upper substrate 10, and in correspondencewith the TFTs 112 of the first lower substrate 11, for blocking lightfrom the regions excluding the first pixel electrodes 111 of the firstlower substrate 11.

FIG. 2 is a top view of the first lower substrate 11 of the conventionalFSC-LCD 1. The TFTs 112 used as pixel switches, data lines 113 forproviding signals to the first pixel electrodes 111 of the first lowersubstrate 11, and gate lines 114 for providing switching signals to theTFTs 112 are provided on the first lower substrate 11. The data lines113 and the gate lines 114 define multiple pixel regions 115. Each ofthe TFTs 112 is on the place in a pixel region 115, where a data line113 and a gate line 114 meet, and is electrically connected to the dataline 113 and the gate line 114.

FIG. 3 is a sequence diagram illustrating a method for driving theconventional FSC-LCD 1. The method for driving the FSC-LCD 1 includes:scanning each of the TFTs 112 according to the first backlight device13, and realigning liquid crystal molecules in the first liquid crystal12 to correspond to the lights emitted by the red LEDs 13 r, green LEDs13 g and blue LEDs 13 b of the first backlight device 13. Specifically,scanning of all of the TFTs (tTFT) 15, liquid crystal response (tLC) 16and backlighting (tBL) 17 in the FSC-LCD 1 are performed in the periodof a field 14.

FIG. 4 illustrates the principle of driving the conventional FSC-LCD 1.The FSC-LCD 1 further includes a first scanning driver 18 and a firstdata driver 19. With reference to FIG. 2, the first lower substrate 11of the FSC-LCD 1 includes multiple pixel regions 115, and pixels in allthe pixel regions 115 form an array. The first scanning driver 18 scanspixels in the pixel regions 115 row by row in sequence, and the firstdata driver 19 transmits the image data to a pixel column correspondingto the pixel regions 115.

However, for good outdoor readability of the conventional FSC-LCD 1discussed-above, the brightness of light produced by the first backlightdevice 13 has to be elevated, resulting in increased power consumption.

In view of the problem in the prior art, the inventors conductedintensive studies with their vast experiences in the field, and inventedthe outdoor-readable LCD of the invention.

SUMMARY OF THE INVENTION

An object of the invention is to solve the drawback of the prior art,provide an outdoor-readable LCD, and realize high brightness for goodoutdoor readability.

To solve the problems above, the invention provides an outdoor-readableLCD, including: a liquid crystal panel including an upper substrate, alower substrate and a liquid crystal layer provided between the uppersubstrate and the lower substrate; a backlight device including aplurality of red LEDs, green LEDs and blue LEDs; and a light sourcecontrol device adapted to adjust the backlight device based on theintensity of ambient light. When the intensity of ambient light is lowerthan a predetermined light intensity of the outdoor-readable LCD, thered LEDs, the green LEDs and the blue LEDs of the backlight device areswitched on in sequence to emit lights with predetermined delays; andwhen the intensity of ambient light is higher than the predeterminedlight intensity, the red LEDs, the green LEDs and the blue LEDs of thebacklight device are switched on at the same time.

As discussed above, the outdoor-readable LCD applies red, green and blue(R, G, B) lights in sequence on the same pixel, for the eyes of theobserver mixing the successive images into a color picture due to theimage sticking, so that the invention without an expensive color filter,can realize outdoor readability, lower costs, improved resolution andlower power consumption, and increase illumination utilization of thebacklight device.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings include:

FIG. 1 is a sectional view of the structure of a conventional FSC-LCD;

FIG. 2 is a top view of the first lower substrate of the conventionalFSC-LCD;

FIG. 3 is a sequence diagram of the conventional FSC-LCD;

FIG. 4 illustrates the principle of driving the conventional FSC-LCD;

FIG. 5 is an exploded view of an outdoor-readable LCD according to theinvention;

FIG. 6( a) and FIG. 6( b) are sequence diagrams for backlight in anoutdoor-readable LCD according to a first embodiment of the invention;

FIG. 7( a) and FIG. 7( b) are sequence diagrams for backlight in anoutdoor-readable LCD according to a second embodiment of the invention;and

FIG. 8 is a sequence diagram for backlight in an outdoor-readableFSC-LCD according to a third embodiment of the invention.

Numerals for the elements in the drawings are listed below:

[Prior art] FSC-LCD  1 First upper substrate  10 First common electrode101 First lower substrate  11 First pixel electrode 111 TFT 112 Dataline 113 Gate line 114 Pixel region 115 First liquid crystal layer  12First backlight device  13 Period  14 Scanning of TFTs  15 Liquidcrystal response  16 Backlighting  17 First scanning driver  18 Firstdata driver  19 [The invention] Outdoor-readable LCD 200 Liquid crystalpanel 210 Second pixel electrode 211 Second low substrate 212 Secondupper substrate 213 Second common electrode 214 Second liquid crystallayer 215 Second backlight device 220 First polarizing plate 221a RedLED 222r Green LED 222g Blue LED 222b White LED 222w Second scanningdriver 230 Second data driver 240

DETAILED DESCRIPTION OF THE INVENTION

The technical solution, structural features, objects and effects of theinvention are described hereinafter in connection with the embodimentsand the figures.

First Embodiment

As shown in FIG. 5, an outdoor-readable LCD 200 of the inventionincludes: a liquid crystal panel 210, a second backlight device 220adapted to illuminate the liquid crystal panel 210, a second scanningdriver 230 adapted to provide a scanning signal to the liquid crystalpanel 210, a second data driver 240 adapted to provide a data signal tothe liquid crystal panel 210, and a light source control device (notshown) adapted to adjust the brightness of the second backlight device220. The liquid crystal panel 210 includes: a second lower substrate 212including second pixel electrodes 211, a second upper substrate 213facing to the second lower substrate 212, a second common electrode 214provided on the side of the second upper substrate 213 facing to thesecond lower substrate 212, and a second liquid crystal layer 215provided between the second lower substrate 212 and the second uppersubstrate 213. The second backlight device 220 includes a plurality ofred LEDs 220 r, green LEDs 220 g and blue LEDs 220 b, and furtherincludes a first polarizing plate 221 a and a second polarizing plate(not shown). The first polarizing plate 221 a is mounted on the side ofthe second lower substrate 212 opposite to the second pixel electrodes211. The second polarizing plate is mounted on the side of the secondupper substrate 213 opposite to the second common electrode 214. The redLEDs 220 r, green LEDs 220 g and blue LEDs 220 b of the second backlightdevice 220 are provided facing to the first polarizing plate 221 a witha certain distance between the second backlight device 220 and the firstpolarizing plate 221 a. When the red LEDs 220 r, green LEDs 220 g andblue LEDs 220 b of the second backlight device 220 are switched on insequence, the red LEDs 220 r, the green LEDs 220 g and the blue LEDs 220b emit red, green and blue lights with predetermined delays; or, the redLEDs 220 r, green LEDs 220 g and blue LEDs 220 b are switched on at thesame time, and the red, green and blue lights emitted are superimposed,resulting in white light.

Particularly, the outdoor-readable LCD according to the invention mayfurther include an ambient light sensor (not shown), adapted to sensethe intensity of ambient light and output a sensing signal. The lightsource control device adjusts the second backlight device 220 based onthe sensing signal.

Now refer to FIG. 6( a) and FIG. 6( b). When the intensity of ambientlight detected by the ambient light sensor is lower than a predeterminedlight intensity of the outdoor-readable LCD 200, the light sourcecontrol device switches on the red LEDs 220 r, the green LEDs 220 g andthe blue LEDs 220 b in sequence according to the sensing signal, and thered LEDs 220 r, the green LEDs 220 g and the blue LEDs 220 b emit red,green and blue lights with predetermined delays. The red, green and bluelights enter the first polarizing plate 221 a, and pass through thesecond lower substrate 212, to the second liquid crystal layer 215.Lights arrived at the second liquid crystal layer 215 pass through thesecond upper substrate 213, and leave from the second polarizing plate,to form a color image. When the intensity of ambient light detected bythe ambient light sensor is higher than the predetermined lightintensity of the outdoor-readable LCD 200, the light source controldevice switches on the red LEDs 220 r, the green LEDs 220 g and the blueLEDs 220 b of the second backlight device 220 at the same time accordingto the sensing signal, and the red LEDs 220 r, the green LEDs 220 g andthe blue LEDs 220 b of the second backlight device 220 emit red, greenand blue lights correspondingly. The red, green and blue lights aresuperimposed into white light. The white light enters the firstpolarizing plate 221 a, and passes through the second lower substrate212, to the second liquid crystal layer 215. Light arrived at the secondliquid crystal layer 215 passes through the second upper substrate 213,and leaves from the second polarizing plate, to form a monochrome imagewith high brightness.

Second Embodiment

This embodiment differs from the first embodiment in the backlightdevice. Specifically, the second backlight device 220 of theoutdoor-readable LCD 200 based on the first embodiment is provided withadditional white LEDs 220 w (not shown). For other arrangementsregarding the outdoor-readable LCD 200, one may refer to the firstembodiment.

Now refer to FIG. 7( a) and FIG. 7( b). When the intensity of ambientlight detected by the ambient light sensor is lower than a predeterminedlight intensity of the outdoor-readable LCD 200, the light sourcecontrol device switches off the white LEDs 220 w, and switches on thered LEDs 220 r, the green LEDs 220 g and the blue LEDs 220 b of thesecond backlight device 220 in sequence according to the sensing signal.The red LEDs 220 r, the green LEDs 220 g and the blue LEDs 220 b emitred, green and blue lights with predetermined delays. The red, green andblue lights enter the first polarizing plate 221 a, and pass through thesecond lower substrate 212, to the second liquid crystal layer 215.Lights arrived at the second liquid crystal layer 215 pass through thesecond upper substrate 213, and leave from the second polarizing plate,to achieve color representation. When the detected intensity of ambientlight is higher than the predetermined light intensity of theoutdoor-readable LCD 200, the white LEDs 220 w are switched on,meanwhile, the red LEDs 220 r, the green LEDs 220 g and the blue LEDs220 b are switched on in sequence to emit red, green and blue lights.The red, green and blue lights enter the first polarizing plate 221 a,and pass through the second lower substrate 212, to the second liquidcrystal layer 215. Lights arrived at the second liquid crystal layer 215pass through the second upper substrate 213, and leave from the secondpolarizing plate. By switching on the white LEDs 220 w, additional whiteback light is provided to the outdoor-readable LCD 200, therebyenhancing its backlight and forming a color image with high brightness.

Third Embodiment

As shown in FIG. 5, an outdoor-readable LCD 200 of the inventionincludes: a liquid crystal panel 210, a second backlight device 220adapted to illuminate the liquid crystal panel 210, a second scanningdriver 230 adapted to provide a scanning signal to the liquid crystalpanel 210, a second data driver 240 adapted to provide a data signal tothe liquid crystal panel 210, and a light source control device (notshown) adapted to adjust the brightness of the second backlight device220. The liquid crystal panel 210 includes: a second lower substrate 212including second pixel electrodes 211, a second upper substrate 213facing the second lower substrate 212, a second common electrode 214provided on the side of the second upper substrate 213 facing to thesecond lower substrate 212, and a second liquid crystal layer 215provided between the second lower substrate 212 and the second uppersubstrate 213. The second backlight device 220 includes a number of redLEDs 220 r, green LEDs 220 g and blue LEDs 220 b, and further includes afirst polarizing plate 221 a and a second polarizing plate. The firstpolarizing plate 221 a is mounted on the side of the second lowersubstrate 212 facing away from the second pixel electrodes 211. Thesecond polarizing plate is mounted on a side of the second uppersubstrate 213 facing away from the second common electrode 214. The redLEDs 220 r, green LEDs 220 g and blue LEDs 220 b of the second backlightdevice 220 are provided facing the first polarizing plate 221 a from acertain distance away. When the red LEDs 220 r, green LEDs 220 g andblue LEDs 220 b of the second backlight device 220 are switched on insequence, the red LEDs 220 r, the green LEDs 220 g and the blue LEDs 220b emit red, green and blue lights with predetermined delays; or, the redLEDs 220 r, green LEDs 220 g and blue LEDs 220 b are switched on at thesame time, and the red, green and blue lights emitted are superimposed,resulting in white light.

Particularly, the outdoor-readable LCD according to the invention mayfurther include an ambient light sensor (not shown), adapted to sensethe intensity of ambient light and output a sensing signal. The lightsource control device adjusts the second backlight device 220 based onthe sensing signal.

Now refer to FIG. 8. When the intensity of ambient light detected by theambient light sensor is lower than a predetermined light intensity ofthe outdoor-readable LCD 200, the light source control device adjusts abias voltage V of the red LEDs 220 r, the green LEDs 220 g and the blueLEDs 220 b of the second backlight device 220 to be zero according tothe sensing signal, and the red LEDs 220 r, the green LEDs 220 g and theblue LEDs 220 b are switched on in sequence to emit red, green and bluelights with predetermined delays. The red, green and blue lights enterthe first polarizing plate 221 a, and pass through the second lowersubstrate 212, to the second liquid crystal layer 215. Lights arrived atthe second liquid crystal layer 215 pass through the second uppersubstrate 213, and leave from the second polarizing plate. When theintensity of ambient light detected by the ambient light sensor ishigher than the predetermined light intensity of the outdoor-readableLCD 200, the light source control device adjusts the bias voltage V ofthe red LEDs 220 r, the green LEDs 220 g and the blue LEDs 220 b of thesecond backlight device 220 according to the sensing signal, by settingthe bias voltage V to a predetermined value according to the intensityof ambient light. Thereby the brightness of backlight provided by thesecond backlight device 220 are elevated, and the red LEDs 220 r, thegreen LEDs 220 g and the blue LEDs 220 b are switched on in sequence toemit red, green and blue lights with predetermined delays. The red,green and blue lights enter the first polarizing plate 221 a, and passthrough the second lower substrate 212, to the second liquid crystallayer 215. Lights arrived at the second liquid crystal layer 215 passthrough the second upper substrate 213, and leave from the secondpolarizing plate, to form a color image with high brightness.

To sum up, the outdoor-readable LCD 200 applies red, green and blue (R,G, B) lights in sequence on the same pixel. The eyes of the observer mixthe successive images into a color picture due to image sticking. Theinvention without an expensive color filter, can realize outdoorreadability, lower costs, lower power consumption and improvedresolution, and increase illumination utilization of the backlightdevice.

Those skilled in the art shall understand that various modifications andalternations of the invention can be made without deviation from thescope of the invention. Accordingly, the invention shall include thosemodifications and alternations within the scope defined by the appendedclaims.

1. An outdoor-readable Liquid Crystal Display (LCD), comprising: aliquid crystal panel, the liquid crystal panel comprising an uppersubstrate, a lower substrate and a liquid crystal layer provided betweenthe upper substrate and the lower substrate; a backlight device,comprising a plurality of red Light-Emitting Diodes (LEDs), green LEDsand blue LEDs; and a light source control device, adapted to adjust thebacklight device based on the intensity of ambient light, wherein, whenthe intensity of ambient light is lower than a predetermined lightintensity of the outdoor-readable LCD, the red LEDs, the green LEDs andthe blue LEDs of the backlight device are switched on in sequence toemit lights with predetermined delays; and when the intensity of ambientlight is higher than the predetermined light intensity, the red LEDs,the green LEDs and the blue LEDs of the backlight device are switched onat the same time.
 2. The outdoor-readable LCD according to claim 1,wherein the backlight device of the outdoor-readable LCD furthercomprises white LEDs, and when the intensity of ambient light is higherthan the predetermined light intensity, the red LEDs, the green LEDs,the blue LEDs and the white LEDs of the backlight device are switched onat the same time.
 3. An outdoor-readable Liquid Crystal Display (LCD),comprising: a liquid crystal panel, the liquid crystal panel comprisingan upper substrate, a lower substrate and a liquid crystal layerprovided between the upper substrate and the lower substrate; abacklight device, comprising a plurality of red Light-Emitting Diodes(LEDs), green LEDs, blue LEDs and white LEDs; and a light source controldevice, adapted to adjust the backlight device based on the intensity ofambient light, wherein, when the intensity of ambient light is lowerthan a predetermined light intensity of the outdoor-readable LCD, thewhite LEDs are switched off, and the red LEDs, the green LEDs and theblue LEDs of the backlight device are switched on in sequence to emitlights with predetermined delays; and when the intensity of ambientlight is higher than the predetermined light intensity, the white LEDsare switched on to emit light, meanwhile, the red LEDs, the green LEDsand the blue LEDs of the backlight device are switched on in sequence toemit lights with predetermined delays.
 4. An outdoor-readable LiquidCrystal Display (LCD), comprising: a liquid crystal panel, the liquidcrystal panel comprising an upper substrate, a lower substrate and aliquid crystal layer provided between the upper substrate and the lowersubstrate; a backlight device, comprising a plurality of redLight-Emitting Diodes (LEDs), green LEDs and blue LEDs; and a lightsource control device, adapted to adjust the backlight device based onthe intensity of ambient light, wherein, when the intensity of ambientlight is lower than a predetermined light intensity of theoutdoor-readable LCD, a bias voltage of the red LEDs, the green LEDs andthe blue LEDs of the backlight device is set to zero, and the red LEDs,the green LEDs and the blue LEDs are switched on in sequence to emitlights with predetermined delays; and when the intensity of ambientlight is higher than the predetermined light intensity, the bias voltageof the red LEDs, the green LEDs and the blue LEDs of the backlightdevice is elevated, and the red LEDs, the green LEDs and the blue LEDsare switched on in sequence to emit lights with predetermined delays. 5.The outdoor-readable LCD according to claim 4, wherein when theintensity of ambient light is higher than the predetermined lightintensity, the increment of the bias voltage of the red LEDs, the greenLEDs and the blue LEDs of the backlight device increases as theintensity of ambient light increases.
 6. The outdoor-readable LCDaccording to claim 1, wherein the outdoor-readable LCD further comprisesan ambient light sensor adapted to detect the intensity of ambient lightand output a sensing signal; and wherein the light source control deviceis adapted to adjust the backlight device based on the sensing signal.7. A method for driving an outdoor-readable Liquid Crystal Display(LCD), wherein the outdoor-readable LCD comprises: a liquid crystalpanel, the liquid crystal panel comprising an upper substrate, a lowersubstrate and a liquid crystal layer provided between the uppersubstrate and the lower substrate; a backlight device, comprising aplurality of red Light-Emitting Diodes (LEDs), green LEDs and blue LEDs;and a light source control device, adapted to adjust the backlightdevice based on the intensity of ambient light, and wherein the methodfor driving the outdoor-readable LCD comprises: when the intensity ofambient light is lower than a predetermined light intensity of theoutdoor-readable LCD, switching on the red LEDs, the green LEDs and theblue LEDs of the backlight device in sequence to emit lights withpredetermined delays; and when the intensity of ambient light is higherthan the predetermined light intensity, switching on the red LEDs, thegreen LEDs and the blue LEDs of the backlight device at the same time.8. A method for driving an outdoor-readable Liquid Crystal Display(LCD), wherein the outdoor-readable LCD comprises: a liquid crystalpanel, the liquid crystal panel comprising an upper substrate, a lowersubstrate and a liquid crystal layer provided between the uppersubstrate and the lower substrate; a backlight device, comprising aplurality of red Light-Emitting Diodes (LEDs), green LEDs, blue LEDs andwhite LEDs; and a light source control device, adapted to adjust thebacklight device based on the intensity of ambient light, and whereinthe method for driving the outdoor-readable LCD comprises: when theintensity of ambient light is lower than a predetermined light intensityof the outdoor-readable LCD, switching off the white LEDs, and switchingon the red LEDs, the green LEDs and the blue LEDs of the backlightdevice in sequence to emit lights with predetermined delays; and whenthe intensity of ambient light is higher than the predetermined lightintensity, switching on the white LEDs to emit light, meanwhile,switching on the red LEDs, the green LEDs and the blue LEDs of thebacklight device in sequence to emit lights with predetermined delays.9. A method for driving an outdoor-readable Liquid Crystal Display(LCD), wherein the outdoor-readable LCD comprises: a liquid crystalpanel, the liquid crystal panel comprising an upper substrate, a lowersubstrate and a liquid crystal layer provided between the uppersubstrate and the lower substrate; a backlight device, comprising aplurality of red Light-Emitting Diodes (LEDs), green LEDs and blue LEDs;and a light source control device, adapted to adjust the backlightdevice based on the intensity of ambient light, and wherein the methodfor driving the outdoor-readable LCD comprises: when the intensity ofambient light is lower than a predetermined light intensity of theoutdoor-readable LCD, setting a bias voltage of the red LEDs, the greenLEDs and the blue LEDs of the backlight device to zero, and switching onthe red LEDs, the green LEDs and the blue LEDs in sequence to emitlights with predetermined delays; and when the intensity of ambientlight is higher than the predetermined light intensity, elevating thebias voltage of the red LEDs, the green LEDs and the blue LEDs of thebacklight device, and switching on the red LEDs, the green LEDs and theblue LEDs in sequence to emit lights with predetermined delays.
 10. Theoutdoor-readable LCD according to claim 2, wherein the outdoor-readableLCD further comprises an ambient light sensor adapted to detect theintensity of ambient light and output a sensing signal; and wherein thelight source control device is adapted to adjust the backlight devicebased on the sensing signal.
 11. The outdoor-readable LCD according toclaim 3, wherein the outdoor-readable LCD further comprises an ambientlight sensor adapted to detect the intensity of ambient light and outputa sensing signal; and wherein the light source control device is adaptedto adjust the backlight device based on the sensing signal.
 12. Theoutdoor-readable LCD according to claim 4, wherein the outdoor-readableLCD further comprises an ambient light sensor adapted to detect theintensity of ambient light and output a sensing signal; and wherein thelight source control device is adapted to adjust the backlight devicebased on the sensing signal.
 13. The outdoor-readable LCD according toclaim 5, wherein the outdoor-readable LCD further comprises an ambientlight sensor adapted to detect the intensity of ambient light and outputa sensing signal; and wherein the light source control device is adaptedto adjust the backlight device based on the sensing signal.